Simplify the following expression: $ z = \dfrac{9y - 3}{-3} - 5 $
In order to add expressions, they must have a common denominator. Multiply the second expression by $\dfrac{-3}{-3}$ $ \dfrac{-5}{1} \times \dfrac{-3}{-3} = \dfrac{15}{-3} $ Therefore $ z = \dfrac{9y - 3}{-3} + \dfrac{15}{-3} $ Now the expressions have the same denominator we can simply add the numerators: $z = \dfrac{9y - 3 + 15}{-3} $ $z = \dfrac{9y + 12}{-3}$ Simplify the expression by dividing the numerator and denominator by -3: $z = \dfrac{-3y - 4}{1}$